The impact of charge carrier relaxation, electron trapping and oxygen p-doping on the photocurrent transients of a conjugated polymer probed by the Time of Flight method

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6–7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut’s appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.

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Determination of the degree of dissociation of an atomic hydrogen target by a recoil-ion time-of-flight method

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/0168-9002(90)91550-u ◽

1990 ◽

Vol 287 (3) ◽

pp. 374-377

Author(s):

J. Euler ◽

J. Ullrich ◽

H. Schmidt-Böcking ◽

H. Vogt

Keyword(s):

Atomic Hydrogen ◽

Time Of Flight ◽

Hydrogen Target ◽

Degree Of Dissociation ◽

Time Of Flight Method

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Carbon Nanotube-Induced Planarization of Conjugated Polymers in Solution

MRS Proceedings ◽

10.1557/proc-858-hh12.4 ◽

2004 ◽

Vol 858 ◽

Cited By ~ 1

Author(s):

Jian Chen ◽

Rajagopal Ramasubramaniam ◽

Haiying Liu

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Conjugated Polymers ◽

Spectroscopic Study ◽

Surface Quality ◽

Hybrid Materials ◽

Conjugated Polymer ◽

Visible Absorption ◽

The Impact ◽

Conformational Interaction

ABSTRACTThe understanding of the conformational interaction between conjugated polymers and carbon nanotubes in solution is essential to develop the applications of carbon nanotubes, particularly conjugated polymer-carbon nanotube hybrid materials. The visible absorption spectroscopic study shows that curved carbon nanotube surfaces can induce the planarization of individual conjugated polymers such as poly(p-phenyleneethynylene)s and poly(3-alkylthiophene)s in solution. The impact of nanotube surface quality on the interaction between carbon nanotubes and conjugated polymers is investigated.

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